Syria's main opposition grouping recorded 15 violations by government troops and allied forces on the first day of a landmark truce, a spokesman told reporters today.

"There were 15 violations by the regime forces on day one of the ceasefire, including two attacks by (Lebanese militant group) Hezbollah in Zabadani" west of Damascus, said Salem al-Meslet, spokesman for the High Negotiations Committee.

Speaking by telephone from Riyadh, Meslet said the HNC would be lodging a formal letter of complaint with UN special envoy Staffan de Mistura, UN chief Ban Ki-moon and the foreign ministers of the International Syria Support Group.

The UN-backed deal came into effect yesterday, with battle zones across the country going largely quiet despite some accusations of breaches.

The HNC announced earlier that 97 opposition factions had agreed to respect the truce, for two weeks initially.

Meslet said none of those groups had responded to the violations yesterday.

"For the opposition forces there, nobody reacted because the decision is to remain quiet and I believe they will stick to the truce."

Meslet said the deal was "the first step in the right direction" to bring an end to the bloody conflict in Syria.

"The thing is, it is positive for us to see people relieved… We have violations here and there, but in general it is a lot better than before and people are comfortable," Meslet said.

"That is our main objective — for our people there to be safe from this fear that has been there for five years now.(Agencies)